Field of the Invention
The present invention relates to an image processing method and image processing apparatus which perform color correction of a facial region after color correction of an image.
Description of the Related Art
Recently, the spread of digital cameras and personal computers has made it possible for users to capture pictures into a personal computer as digital images and freely perform image processing using application software which corrects images.
The image processing includes correction used to increase brightness of, for example, an underexposed dark image and correction used to change flesh color affected by a color cast into appropriate flesh color.
Against this background, more accurate image processing techniques have recently become necessary. In particular, advancement in object extraction techniques has made it possible to automatically detect human faces in an image. Consequently, many techniques have been proposed for determining feature values in a facial region of a person and correcting brightness and colors of the image appropriately according to the feature values.
For example, Japanese Patent Laid-Open No. 2001-148863 proposes a technique which detects flesh color of a person in an image and determines hue difference between the flesh color subjected to white balance correction and a target color, before performing white balance correction of the image using a highlight point in the image. If the hue difference is decreased, the technique performs white balance correction, but if the hue difference is increased, the technique does not perform white balance correction.
However, the conventional method described above has a problem in that results of correction vary greatly with the accuracy of face detection because white balance correction is not performed if the flesh color of a person deviates even slightly from the target color. Besides, it is not always possible to make the flesh color of a person match the target color by white balance correction alone.